US6769514B2 - Helicopter lineman's ladder and method for energized powerline repair - Google Patents
Helicopter lineman's ladder and method for energized powerline repair Download PDFInfo
- Publication number
- US6769514B2 US6769514B2 US10/036,387 US3638702A US6769514B2 US 6769514 B2 US6769514 B2 US 6769514B2 US 3638702 A US3638702 A US 3638702A US 6769514 B2 US6769514 B2 US 6769514B2
- Authority
- US
- United States
- Prior art keywords
- ladder
- lineman
- helicopter
- elongate
- tower
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
- E06C—LADDERS
- E06C7/00—Component parts, supporting parts, or accessories
- E06C7/08—Special construction of longitudinal members, or rungs or other treads
-
- E—FIXED CONSTRUCTIONS
- E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
- E06C—LADDERS
- E06C1/00—Ladders in general
- E06C1/02—Ladders in general with rigid longitudinal member or members
- E06C1/34—Ladders attached to structures, such as windows, cornices, poles, or the like
- E06C1/36—Ladders suspendable by hooks or the like
-
- E—FIXED CONSTRUCTIONS
- E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
- E06C—LADDERS
- E06C1/00—Ladders in general
- E06C1/02—Ladders in general with rigid longitudinal member or members
- E06C1/38—Special constructions of ladders, e.g. ladders with more or less than two longitudinal members, ladders with movable rungs or other treads, longitudinally-foldable ladders
-
- E—FIXED CONSTRUCTIONS
- E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
- E06C—LADDERS
- E06C1/00—Ladders in general
- E06C1/02—Ladders in general with rigid longitudinal member or members
- E06C1/38—Special constructions of ladders, e.g. ladders with more or less than two longitudinal members, ladders with movable rungs or other treads, longitudinally-foldable ladders
- E06C1/39—Ladders having platforms; Ladders changeable into platforms
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G1/00—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines
- H02G1/02—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines for overhead lines or cables
Definitions
- High voltage powerlines carrying voltages in the hundreds of kilowatt range have been constructed to extend from spaced towers high above terrain which is often practically inaccessible to land vehicles.
- a number of methods and devices have been developed to facilitate the repair of remote high voltage powerlines which are accessed by helicopter.
- Helicopter transported landing platforms and work scaffolds which can be attached to the cross arm of a utility pole have been developed to permit a lineman to disembark from a helicopter and descend vertically along the utility pole to the powerlines supported thereby.
- Such devices are heavy and bulky, and are often difficult to maneuver. More importantly, however, is the fact that these devices position a lineman in close proximity to a grounded utility pole, so that the powerlines must be deenergized before repair can occur. Otherwise it is dangerous for a lineman to remain in the electrically charged space between energized high voltage conductors and a grounded tower or utility pole.
- a helicopter-mountable landing platform and work scaffold adapted to be mounted by a utility pole is illustrated in U.S. Pat. No. 3,863,736 to McWilliams.
- linemen In order to avoid an extensive power outage which might occur when a high voltage powerline is deenergized for repair, it is desirable to provide live maintenance on energized high voltage conductors. To accomplish this, linemen first bond to the energized transmission line to become energized to the same potential as that of the line. This permits the lineman to work safely on the energized line so long as he maintains sufficient spacing from grounded structures, such as support towers, to prevent the risk of flashover. To facilitate live maintenance on energized high voltage powerlines, various lineman support structures have been developed which are suspended from a helicopter over a powerline pair remote from the support towers. These support structures are formed either partially or totally from electrically conductive material and include skids or rollers which engage a pair of parallel lines.
- Another object of the present invention is to provide a novel and improved lineman's ladder which is lightweight and which can be lowered from a helicopter and easily positioned between a tower cross arm and energized conductors by a single lineman.
- Yet another object of the present invention is to provide a novel and improved helicopter lineman's ladder which will deliver a lineman from a tower to energized powerlines and insure that the lineman is a safe distance from the tower before the lineman bonds to an energized powerline.
- a still further object of the present invention is to provide a novel and improved helicopter lineman's ladder which operates to prevent a lineman who has bonded to an energized powerline from inadvertently moving dangerously close to a grounded tower.
- a rigid ladder having one end which hooks to a powerline support bridge after the ladder is dropped by helicopter.
- the ladder includes a first section which extends out from the support bridge for the flashover distance to the tower or more, and a second section that extends downwardly from the outer end of the first section to a base which rests on the powerlines spaced from the support bridge.
- a weight on the base holds it against the powerlines, and the complete structure is formed of electrically nonconductive material.
- FIG. 1 is a perspective view of high voltage tower supported powerlines
- FIG. 2 is a perspective view of the helicopter lineman's ladder of the present invention
- FIG. 3 is a view in side elevation of the helicopter lineman's ladder of FIG. 2;
- FIG. 4 is a perspective view of a second embodiment of the helicopter lineman's ladder of the present invention.
- high voltage AC transmission lines normally include at least three powerline conductors 2 , 4 and 6 , with each powerline conductor carrying a voltage which is 120° out of phase with the voltages carried by the remaining conductors. These powerline conductors extend over substantial distances and are supported to extend between spaced towers 8 and 10 . Each powerline conductor is suspended beneath a tower cross arm 12 by elongate insulators 14 .
- a helicopter 16 offloads one or more linemen 18 directly onto a tower 8 .
- This can be accomplished by having linemen sit on a helicopter skid 20 or upon a platform placed across the helicopter skids which extends laterally of the helicopter.
- the problem to be solved is how the lineman can safely descend to the energized powerline conductors 2 , 4 and 6 and bond onto a conductor to raise his body voltage to the powerline conductor voltage. This cannot be done from the grounded tower structure or even from within an area close to the tower structure where flashover can occur. A flashover area, indicated at 22 , must be avoided if live maintenance on energized powerline conductors is to be safely accomplished. OSHA safety regulations require that a flashover area of at least eleven feet from the tower be maintained for energized high voltage transmission line repair and that this area must be avoided by linemen bonded to a powerline conductor.
- a one piece, unitary lineman's ladder indicated generally at 24 is provided to ensure that a lineman can safely descend from the tower, bond onto an energized conductor, accomplish conductor repair, and ascend back to the tower without danger of ever entering the flashover area 22 while energized.
- the lineman's ladder 24 includes a first elongate section 26 having a free end which terminates in a pair of spaced connectors 28 which are adapted to engage and be connected to the tower cross arm 12 of a tower 8 .
- These connectors are shown as hooks in FIG. 1, but may take a number of forms to permit a lineman to positively lock the free end of the elongate section 26 to the tower cross arm.
- These connectors can be, for example, hooks with pivoted locking arms, hooks in combination with belts to secure the ladder to the cross arm, belts alone, or other known locking connectors to secure the ladder to the cross arm.
- a second elongate section 30 of the lineman's ladder extends from the end of the section 26 at an angle no less than ninety degrees and which is preferably greater than ninety degrees.
- the section 30 terminates in a curved base bar 32 which extends outwardly on either side of the section 30 and terminates in downwardly turned ends 34 and 36 .
- Extending below the base bar on a flexible tether 38 is a weight 40 .
- the elongate sections 26 and 30 of the lineman's ladder 24 are formed as ladder sections with spaced side bars 42 joined by cross rungs 44 . All components of the lineman's ladder, including the sections 24 and 30 , the connectors 28 , the base bar 32 , the tether 38 and the weight 40 are preferably formed of electrically nonconductive material.
- the ladder is very light weight and maneuverable and can easily be carried and lowered from a helicopter and secured in place by a lineman who was previously offloaded onto the tower 8 .
- the length of the elongate section 26 must be sufficient to insure that a lineman descending down the section 30 to an energized line is outside the flashover area 22 .
- the length of the section 26 is eleven feet or more to position the section 30 outside the flashover zone.
- the section 30 will normally be shorter than the section 24 as its length must merely be sufficient to enable a lineman to reach the conductors supported below the tower cross arm 12 .
- the lineman's ladder 24 is lowered to the lineman from the helicopter. Rings 46 may be secured to the sidebars 42 between the sections 26 and 30 to facilitate attachment to a helicopter cable.
- the lineman positions the ladder over a conductor or conductors and attaches the spaced connectors 28 to the tower cross arm 12 .
- the base bar 32 is lowered into engagement with a conductor or conductors and is held in place by the tethered weight 40 .
- the lineman now descends to the base bar, and while standing on the insulated base bar, bonds to the energized conductor. Now, the lineman can step onto the conductor to perform repairs.
- FIG. 4 illustrates a second embodiment of the unitary lineman's ladder which is indicated generally at 48 .
- structural elements which are the same as those previously described with reference to FIGS. 2 and 3 will be designated with like reference numerals.
- the ladder rungs 44 in elongate section 26 are eliminated and a solid ramp 50 extends between the sidebars 42 .
- handrails 52 are attached to the sidebars 42 of the elongate section 26 on either side of the ramp 50 . These handrails can be attached to a helicopter lowering cable.
- the base bar 32 , tether 38 and weight 40 of the lineman's ladder 24 are replaced by a platform 54 secured to the bottom of the section 30 .
- This platform supports weights 56 shown by broken lines in FIG. 4 which hold the platform in engagement with an energized conductor.
- Downward spaced projections 58 formed on either side of the bottom of the platform 54 extend on either side of a conductor which the platform engages.
- all components of the lineman's ladder 48 are formed of electrically nonconductive material.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Architecture (AREA)
- Structural Engineering (AREA)
- Insulating Bodies (AREA)
- Insulators (AREA)
- Electric Cable Installation (AREA)
Abstract
Description
Claims (18)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/036,387 US6769514B2 (en) | 2002-01-07 | 2002-01-07 | Helicopter lineman's ladder and method for energized powerline repair |
US10/414,307 US6675935B2 (en) | 2002-01-07 | 2003-04-16 | Helicopter lineman's ladder and method for energized powerline repair |
US10/868,141 US6994186B2 (en) | 2002-01-07 | 2004-06-15 | Helicopter lineman's ladder |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/036,387 US6769514B2 (en) | 2002-01-07 | 2002-01-07 | Helicopter lineman's ladder and method for energized powerline repair |
Related Child Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/414,307 Division US6675935B2 (en) | 2002-01-07 | 2003-04-16 | Helicopter lineman's ladder and method for energized powerline repair |
US10/868,141 Continuation US6994186B2 (en) | 2002-01-07 | 2004-06-15 | Helicopter lineman's ladder |
Publications (2)
Publication Number | Publication Date |
---|---|
US20030127288A1 US20030127288A1 (en) | 2003-07-10 |
US6769514B2 true US6769514B2 (en) | 2004-08-03 |
Family
ID=21888330
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/036,387 Expired - Lifetime US6769514B2 (en) | 2002-01-07 | 2002-01-07 | Helicopter lineman's ladder and method for energized powerline repair |
US10/414,307 Expired - Lifetime US6675935B2 (en) | 2002-01-07 | 2003-04-16 | Helicopter lineman's ladder and method for energized powerline repair |
US10/868,141 Expired - Lifetime US6994186B2 (en) | 2002-01-07 | 2004-06-15 | Helicopter lineman's ladder |
Family Applications After (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/414,307 Expired - Lifetime US6675935B2 (en) | 2002-01-07 | 2003-04-16 | Helicopter lineman's ladder and method for energized powerline repair |
US10/868,141 Expired - Lifetime US6994186B2 (en) | 2002-01-07 | 2004-06-15 | Helicopter lineman's ladder |
Country Status (1)
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US (3) | US6769514B2 (en) |
Cited By (6)
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US20090039325A1 (en) * | 2007-08-07 | 2009-02-12 | Gunter Samuel N | Apparatus and method for stringing aerial cables using aircraft |
US20090101439A1 (en) * | 2007-10-22 | 2009-04-23 | Haverfield International Incorporated | Transfer platform |
RU2481683C1 (en) * | 2011-12-14 | 2013-05-10 | Открытое акционерное общество Научно-производственная компания "Применение авиации в народном хозяйстве" ОАО НПК "ПАНХ" | Method to install flexible element by means of helicopter |
US20150259979A1 (en) * | 2014-03-11 | 2015-09-17 | Daifuku Co., Ltd. | Ladder and Storage Rack Maintenance Facility Including the Same |
US20180371837A1 (en) * | 2017-06-22 | 2018-12-27 | Kurt A. Heiss | Ladder weight |
US10974939B2 (en) | 2017-11-09 | 2021-04-13 | Quanta Associates, L.P. | Inductor to control transient currents during energized bond on |
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US20030071433A1 (en) * | 2001-10-11 | 2003-04-17 | Rammer George J. | Compact, self supporting and folding equipment access assembly |
US8225906B2 (en) | 2008-08-22 | 2012-07-24 | Core Distribution, Inc. | Extendable/retractable ladder |
CN102966301B (en) * | 2012-11-14 | 2014-08-06 | 国家电网公司 | Live working sliding board |
CN103633579B (en) * | 2013-11-12 | 2016-11-23 | 国家电网公司 | A kind of multipurpose safety Work tool right angle hanging ladder |
US9404305B1 (en) * | 2014-03-26 | 2016-08-02 | Mark S. Messick | Portable and adaptable platform |
CN104201601A (en) * | 2014-07-10 | 2014-12-10 | 国家电网公司 | Sectional assembly type insulation payoff rigid ladder of 500 kV overhead power transmission line |
US10233692B2 (en) * | 2014-12-02 | 2019-03-19 | Core Distribution, Inc. | Foldable ladder |
US9580959B2 (en) * | 2014-12-02 | 2017-02-28 | Core Distribution, Inc. | Foldable ladder |
US9416591B2 (en) | 2014-12-02 | 2016-08-16 | Core Distribution, Inc. | Telescoping ladder with stabilizers |
CN105952369B (en) * | 2016-04-28 | 2017-11-10 | 国家电网公司 | A kind of maintenance ladder docked with transmission of electricity tower bar fixed ladder |
CN106014184B (en) * | 2016-05-18 | 2017-10-31 | 国家电网公司 | A kind of 500kV transmission lines of electricity ladder for getting down transmission line stabilising arrangement |
CN106285448B (en) * | 2016-08-22 | 2018-05-08 | 国网山东省电力公司昌乐县供电公司 | Hanging ladder is overhauled in the distribution of three-point mount formula |
CN107178303A (en) * | 2017-03-03 | 2017-09-19 | 厦门新技术集成有限公司 | The double ladder that a kind of convertible vertical ladder is used |
US11174678B2 (en) | 2017-11-08 | 2021-11-16 | Core Distribution, Inc. | Locking assembly for a telescoping ladder |
CN107910809B (en) * | 2017-11-28 | 2019-10-01 | 国网山东省电力公司济南供电公司 | A kind of hot line maintenance insulated ladder |
CN108915230B (en) * | 2018-07-25 | 2021-03-05 | 江苏鑫鹏电力工程有限公司 | Adjustable multifunctional electric power overhaul safety protection device |
CN109193467B (en) * | 2018-11-06 | 2020-07-07 | 国网四川省电力公司资阳供电公司 | Transmission line overhauls cat ladder |
CN110649504B (en) * | 2019-07-22 | 2021-05-04 | 国网浙江省电力有限公司湖州供电公司 | Insulating flat ladder of 500kV strain insulator shaft tower live working |
US11795760B2 (en) * | 2019-10-24 | 2023-10-24 | Core Distribution, Inc. | Ladder tripod assembly and system |
CN111058759B (en) * | 2019-11-15 | 2021-05-07 | 国能濮阳热电有限公司 | Boiler overhauls device suitable for thermal power station factory building |
CN113236109B (en) * | 2021-04-21 | 2022-12-30 | 国网吉林省电力有限公司检修公司 | Automatic wire hanging device for power transmission line |
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US6269909B1 (en) | 1999-11-15 | 2001-08-07 | Fiberlite Technologies, Inc. | Fiberglass extension ladder and methods for manufacturing the same |
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- 2002-01-07 US US10/036,387 patent/US6769514B2/en not_active Expired - Lifetime
-
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- 2003-04-16 US US10/414,307 patent/US6675935B2/en not_active Expired - Lifetime
-
2004
- 2004-06-15 US US10/868,141 patent/US6994186B2/en not_active Expired - Lifetime
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US1942210A (en) * | 1932-07-28 | 1934-01-02 | Harting Walter | Universal folding ladder |
US2760707A (en) * | 1951-07-09 | 1956-08-28 | Safway Steel Products Inc | Scaffold stair unit |
US3196980A (en) * | 1961-10-27 | 1965-07-27 | Harold L Rorden | Insulated personnel carrier |
US3402786A (en) * | 1966-10-06 | 1968-09-24 | Lewis H. White | Personnel protective equipment for working energized conductors |
US3734237A (en) | 1971-03-16 | 1973-05-22 | Howard Manuf Co | Ladder |
US3863736A (en) | 1973-05-31 | 1975-02-04 | Decair Helicopters Inc | Helicopter-mountable landing platform and work scaffold and method of placing same in operating position |
US3954156A (en) * | 1974-03-06 | 1976-05-04 | Samuel Kennedy | Ladder assembly |
US4084812A (en) * | 1975-10-31 | 1978-04-18 | Game Time, Inc. | Playground swing apparatus |
US4029172A (en) | 1976-07-12 | 1977-06-14 | Composite Technology, Inc. | Fiberglass ladder and method of constructing same |
USD256040S (en) * | 1978-07-31 | 1980-07-22 | Recreation Systems Co. | Child recreation climber structure |
US4422528A (en) | 1981-04-13 | 1983-12-27 | Columbia Helicopters, Inc. | Aerial basket structure for linemen and method for utilizing same |
US4401184A (en) * | 1982-03-22 | 1983-08-30 | Sherry Howard W | Roof skid |
US4478312A (en) | 1982-09-30 | 1984-10-23 | Kurtgis Michael P | System and portable cage for servicing power transmission lines |
US4673059A (en) | 1982-12-20 | 1987-06-16 | Kurtgis Michael P | Placement of load onto energized transmission line system |
US4637575A (en) | 1984-10-04 | 1987-01-20 | Yenzer Scott H | Helicopter airmobile work platform for working on power lines and tower structures |
US5273239A (en) | 1990-11-19 | 1993-12-28 | Electricite De France Service National | Modulable helicopter-carried nacelle to be placed on overhead cables |
US5474259A (en) | 1991-04-29 | 1995-12-12 | Electricite De France Service National | Process for intervention on overhead cables by means of helicopter-carried fork and nacelle |
US5328133A (en) | 1993-07-30 | 1994-07-12 | Marc Charest | System for carrying equipment and/or a workman to a high voltage line or installations |
US5494132A (en) | 1994-02-14 | 1996-02-27 | Hansen; Harry L. | Side-loading suspension frame and ladder assembly for maintenance of energized power transmission lines |
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Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090039325A1 (en) * | 2007-08-07 | 2009-02-12 | Gunter Samuel N | Apparatus and method for stringing aerial cables using aircraft |
US8156624B2 (en) * | 2007-08-07 | 2012-04-17 | Gunair LLC | Apparatus and method for stringing aerial cables using aircraft |
US8439332B2 (en) * | 2007-08-07 | 2013-05-14 | Gunair LLC | Apparatus and method for stringing aerial cables using aircraft |
US20090101439A1 (en) * | 2007-10-22 | 2009-04-23 | Haverfield International Incorporated | Transfer platform |
US7931121B2 (en) | 2007-10-22 | 2011-04-26 | Haverfield International Incorporated | Transfer platform |
RU2481683C1 (en) * | 2011-12-14 | 2013-05-10 | Открытое акционерное общество Научно-производственная компания "Применение авиации в народном хозяйстве" ОАО НПК "ПАНХ" | Method to install flexible element by means of helicopter |
US20150259979A1 (en) * | 2014-03-11 | 2015-09-17 | Daifuku Co., Ltd. | Ladder and Storage Rack Maintenance Facility Including the Same |
US20180371837A1 (en) * | 2017-06-22 | 2018-12-27 | Kurt A. Heiss | Ladder weight |
US10974939B2 (en) | 2017-11-09 | 2021-04-13 | Quanta Associates, L.P. | Inductor to control transient currents during energized bond on |
Also Published As
Publication number | Publication date |
---|---|
US20030192742A1 (en) | 2003-10-16 |
US6994186B2 (en) | 2006-02-07 |
US20040222041A1 (en) | 2004-11-11 |
US20030127288A1 (en) | 2003-07-10 |
US6675935B2 (en) | 2004-01-13 |
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